Definition of Topotaxy

Shannon, R. D.; Rossi, Ronald C.

doi:10.1038/2021000a0

Cited by 56 publications

(49 citation statements)

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“…In as-synthesized LMR-NMC the C2/m component exists as domains of Li 2 MnO 3 thick enough to diffract, but after even the very first charge/discharge cycle, the lithium-richer C2/m component reforms in thin layers that interlayer with the R-3m phase in what could be termed an electrochemical topotaxy. 22,23 This thinly interlayered C2/m component is perhaps too thin to diffract but present in enough effective volume to produce detectable Raman scattering. Having advanced this thought, we do recognize that there are other credible explanations for the disappearance of the Li 2 MnO 3 "ordering" lines.…”

Section: Discussionmentioning

confidence: 99%

A Raman-Based Investigation of the Fate of Li₂MnO₃in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

Maroni

Gosztola

et al. 2015

J. Electrochem. Soc.

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The relationship between structure and electrochemical performance of lithium-and manganese-rich cathode materials with the general formula xLi 2 MnO 3 •(1-x)LiMO 2 is under intensive study world-wide in the context of its importance to the development of high energy/high capacity lithium batteries. One of the issues raised in these studies is the fate of the Li 2 MnO 3 component as a function of voltage and repeated cycling. We have performed Raman spectroscopy based measurements that shed light on the transformations of the Li 2 MnO 3 phase as a function of state-of-charge. We find that on charging the Li 2 MnO 3 phase appears to de-lithiate at a rate at least equal to that of the LiMO 2 phase, whereas, on discharge a Li 2 MnO 3 -like component reforms later in the discharge than does the LiMO 2 phase. The absence of X-ray diffraction evidence for the presence of Li 2 MnO 3 after the first charge/discharge cycle can be reconciled by the possibility that the C2/m structured Li 2 MnO 3 exists in domains thick enough to diffract; but during subsequent discharging, a perturbed C2/m phase forms in conjunction with the re-lithiated LiMO 2 phase in thin sheets (electrochemically induced topotaxy) that are not thick enough to diffract but form in sufficient volume to give Raman scattering similar to that of In contrast to conventional layered cathode materials for lithium ion batteries, such as LiNi x Co y Mn z O 2 with x + y + z ∼ = 1.0 leading to an R-3m-like structure, the lithium-and manganese-rich version of this composition (often designated as LMR-NMC) has a layered-layered structure that can be better described as xLi 2 MnO 3 · (1-x)LiMO 2 (M = Ni-Mn-Co).1 It has been clearly demonstrated that this LMR-NMC material consists of not only the R-3m phase but also the Li 2 MnO 3 phase with C2/m structure, with the two structures integrated at the domain level. The two component nature of the pristine material has been investigated by a wide range of techniques, including electrochemistry, X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), transmission electron microscopy (TEM), nuclear magnetic resonance spectroscopy (NMR), and Raman spectroscopy. The high lithium content in the C2/m phase gives LMR-NMC a much higher energy density making it a promising high energy cathode material for lithium ion batteries. Whereas it has been clearly demonstrated that the C2/m phase is no longer detected, e.g., by XRD, after activation at high voltage against lithium (see for example Li et al.2 ), Yu and Yanagida 3 claim evidence for a synergetic relationship between the C2/m component and the R-3m component of LMR-NMC materials wherein the two layered phases stabilize one another during charge and discharge. In prior publications our group showed that the Li 2 MnO 3 component activated in the first charge/discharge cycle is continuously active throughout the whole operating voltage window (2.0 to 4.6 V) during the charge process, but is more active below 3.6 V during the discharge process. [4][5] Ongoing research rela...

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Section: Discussionmentioning

confidence: 99%

A Raman-Based Investigation of the Fate of Li₂MnO₃in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

Maroni

Gosztola

et al. 2015

J. Electrochem. Soc.

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“…studying the orientation of the product phase with respect to that of the reactant. If the transformation occurs so that the orientation of the product phase is correlated with the orientation of the reactant phase, then a topotactical relation is said to exist* (Lotgering, 1959;Shannon and Rossi, 1963). q;…”

Section: Introductionmentioning

confidence: 99%

Topotaxy in the Anataserutile Transformation

Shannon

Pask

1964

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“…In this case the morphology of the original single crystal is retained, yielding a single crystal of the new phase, even though significant changes occur in both the packing of the B12 icosahedra and placement of interstitial atoms. Several examples of similar rearrangements have recently been reported in the literature and are described as topotactic reactions (Lotgering, 1959;Shannon & Rossi, 1964).…”

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Topotactic transition in C₄AlB₂₄

Giese¹,

Economy²,

Matkovich³

1966

Acta Cryst

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Definition of Topotaxy

Cited by 56 publications

References 6 publications

A Raman-Based Investigation of the Fate of Li₂MnO₃in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

A Raman-Based Investigation of the Fate of Li₂MnO₃in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

Topotaxy in the Anataserutile Transformation

Topotactic transition in C₄AlB₂₄

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Definition of Topotaxy

Cited by 56 publications

References 6 publications

A Raman-Based Investigation of the Fate of Li2MnO3in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

A Raman-Based Investigation of the Fate of Li2MnO3in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

Topotaxy in the Anataserutile Transformation

Topotactic transition in C4AlB24

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A Raman-Based Investigation of the Fate of Li₂MnO₃in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

A Raman-Based Investigation of the Fate of Li₂MnO₃in Lithium- and Manganese-Rich Cathode Materials for Lithium Ion Batteries

Topotactic transition in C₄AlB₂₄